Refractive-Diffractive Multifocal Lens

ABSTRACT

Aspects of the present invention provide multifocal lenses having one or more multifocal inserts comprising one or more diffractive regions. A diffractive region of a multifocal insert of the present invention can provide a constant optical power or can provide a progression of optical power, or any combination thereof. A multifocal insert of the present invention can be fabricated from any type of material and can be inserted into any type of bulk lens material. A diffractive region of a multifocal insert of the present invention can be positioned to be in optical communication with one or more optical regions of a host lens to provide a combined desired optical power in one or more vision zones. Index matching layers of the preset invention can be used to reduce reflection losses at interfaces of the host lens and multifocal insert.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/005,876, filed on Jan. 13, 2011, which is a continuation of U.S.patent application Ser. No. 12/270,116, filed on Nov. 13, 2008, which isa continuation-in-part of U.S. patent application Ser. No. 12/059,908,filed on Mar. 31, 2008 which is a continuation-in-part of U.S. patentapplication Ser. No. 11/964,030, filed on Dec. 25, 2007.

U.S. patent application Ser. No. 12/270,116 is also acontinuation-in-part of U.S. patent application Ser. No. 12/238,932,filed on Sep. 26, 2008. The contents of each of the above-referencedapplications are hereby incorporated by reference in their entireties.

This application claims priority from and incorporates by reference intheir entirety the following provisional applications:

-   U.S. Appl. No. 61/013,822, filed on Dec. 14, 2007;-   U.S. Appl. No. 61/030,789, filed on Feb. 22, 2008;-   U.S. Appl. No. 61/038,811, filed on Mar. 24, 2008;-   U.S. Appl. No. 60/970,024, filed on Sep. 5, 2007;-   U.S. Appl. No. 60/956,813, filed on Aug. 20, 2007;-   U.S. Appl. No. 60/935,573, filed on Aug. 20, 2007;-   U.S. Appl. No. 60/935,492, filed on Aug. 16, 2007;-   U.S. Appl. No. 60/935,226, filed on Aug. 1, 2007;-   U.S. Appl. No. 60/924,975, filed on Jun. 7, 2007;-   U.S. Appl. No. 60/907,367, filed on Mar. 29, 2007;-   U.S. Appl. No. 60/978,776, filed on Oct. 10, 2007;-   U.S. Appl. No. 60/960,606, filed on Oct. 5, 2007;-   U.S. Appl. No. 60/960,607, filed on Oct. 5, 2007;-   U.S. Appl. No. 60/907,097, filed on Mar. 21, 2007; and-   U.S. Appl. No. 60/905,304, filed on Mar. 7, 2007.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to lenses. More specifically,the present invention provides an insert having a diffractive regionthat can be embedded into any host lens material to form a multifocallens.

2. Background Art

There is a desire to improve the performance and cosmetic appeal ofmultifocal lenses. Traditional multifocal lenses; such as bifocal andtrifocals, suffer from a number of disadvantages. As an example, manytraditional multifocal lenses have a visible discontinuity separatingeach vision zone. Blended multifocals can reduce the visibilityassociated with these abrupt discontinuities but generally at the costof rendering the blend zones optically unusable due to high levels ofdistortion and/or astigmatism. Traditional progressive lenses canprovide multiple vision zones with invisible boundaries and no imagebreaks but these lenses typically have narrow vision zones and areassociated with large amounts of unwanted astigmatism.

Diffractive optical structures have many adventures over refractiveoptical structures and can reduce the visibility of discontinuitiesbetween vision zones when used to construct multifocal lenses. However,lenses using diffractive optical structures to date have suffered from anumber of compromises including severe chromatic aberration due todispersion and ghosting due to poor diffraction efficiency.

Accordingly, what is needed is multifocal lens that exploits theadvantages of diffractive optical structures to provide less visiblediscontinuities while additionally reducing vision compromises commonlyassociated with diffractive optics.

BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES

FIG. 1 illustrates a multifocal lens according to an aspect of thepresent invention.

FIG. 2 illustrates a front view and a corresponding cross-sectional viewof a first multifocal lens of the present invention.

FIG. 3 illustrates a front view and a corresponding cross-sectional viewof a second multifocal lens of the present invention.

FIG. 4 illustrates a front view and a corresponding cross-sectional viewof a third multifocal lens of the present invention.

FIG. 5 illustrates a front view and a corresponding cross-sectional viewof a fourth multifocal lens of the present invention.

FIG. 6 illustrates a process for fabricating a multifocal lens of thepresent invention.

FIG. 7 illustrates a close-up view of a possible alignment of adiffractive and a progressive optical power region in accordance with anaspect of the present invention

DETAILED DESCRIPTION OF THE INVENTION

Aspects of the present invention provide multifocal lenses having one ormore multifocal inserts comprising one or more diffractive regions. Adiffractive region of a multifocal insert of the present invention canprovide a constant optical power or can provide a progression of opticalpower, or any combination thereof. A multifocal insert of the presentinvention can be fabricated from any type of material and can beinserted into any type of bulk lens material. A diffractive region of amultifocal insert of the present invention can be positioned to be inoptical communication with one or more optical regions of a host lens toprovide a combined desired optical power in one or more vision zones.Index matching layers of the present invention can be used to reducereflection losses at interfaces of the host lens and multifocal insert.

A multifocal insert of the present invention can be applied to any typeof optical lens or device including ophthalmic lenses such as, but notlimited to, contact lenses, intra-ocular lenses, corneal in-lays,corneal on-lays, and spectacle lenses.

The multifocal lens of the present invention can be a finished lens(edge and ready to mount in a frame), a finished lens blank (not yetedge and ready to mount in a frame), a semi-finished lens blank(finished on at least one outer surface but not yet finished on a secondouter surface) or a non-finished lens blank (having neither outersurface finished). Further, the present invention allows for anyreflective or diffractive optical power including plane (i.e., nooptical power).

FIG. 1 illustrates a multifocal lens 100 according to an aspect of thepresent invention. The multifocal lens 100 can comprise host lensmaterial or layer 102 and an insert or internal layer 104. The host lensmaterial 102 and the insert 104 can comprise different materials havingdifferent indices of refraction. The host lens material 102 and theinsert 104 can comprise substantially homogeneous materials. The hostlens material 102 can have an index of refraction that ranges, forexample, from 1.30 to 2.0. The insert 104 can have a different index ofrefraction that also ranges, for example, from 1.30 to 2.0 The host lensmaterial 102 can be considered to be bulk lens material.

The multifocal lens 100 can be finished, non-finished, or semi-finishedlens blank. The multifocal lens 100 can be a final ophthalmic lens. Themultifocal lens 100 can be subjected to or can include modificationsfrom any know lens processing including, but not limited to, tinting(e.g., including adding a photochromic), anti-reflection coating,anti-soiling coating, scratch resistance hard coating, ultra-violetcoating, selective filtering of high energy light, drilling, edgingsurfacing, polishing and free forming or direct digital surfacing.

The multifocal lens 100 can be a static lens. For example, themultifocal lens 100 can be a bifocal, trifocal or multifocal lens, alens having a progressive addition surface, a lens having a diffractivesurface, a lens having a progressive region of optical power or anycombination thereof. Overall, the multifocal lens can be any lens havingone or more regions of constant or fixed optical power, includingdifferent optical powers.

The multifocal lens 100 can be a dynamic lens. For example, themultifocal lens 100 can be an electro-active lens, a fluid lens, amechanically focusing lens, or a membrane spectacle lens. Overall, themultifocal lens 100 can be any lens capable of having its externalconvex and/or concave curvature altered mechanically or manually, or itsoptical power or depth of focus changed or altered in a dynamic manner.

The insert 104 can comprise one or more diffractive regions. Thediffractive region can be a static (e.g., non-dynamic ornon-electro-active) or a dynamic electro-active diffractive region, orany combination thereof. The diffractive region can provide constantoptical power, a progression of optical power or a combination thereof.The diffractive region of the insert 104 can provide discrete changes inoptical power without the abrupt sag or slope discontinuities of aconventional refractive surface. As an electro-active diffractiveregion, the diffractive region can provide an alterable optical power.The diffractive region of the insert 104 can also be cropped or blended.Cropping can reduce the size of the diffractive region (e.g., byremoving or not forming a portion of a concentric ring of a typicaldiffractive structure) while maintaining a desired shape and effectiveoptical power. Overall, a diffractive region of the insert 104 can be orcan exhibit any of the characteristics (e.g., variation in shape, size,orientation, positioning, blending, cropping, optical power provided,fabrication, blending efficiency, etc. ) of any of the diffractiveregions described in U.S. patent application Ser. No. 12/166,526, filedon Jul. 2, 2008, which is hereby incorporated by reference in itsentirety.

The insert 104 can be fabricated as an optical film, an optical wafer, arigid optic or a lens blank. The diffractive region of the insert 104can be fabricated, for example, to have a thickness ranging from 1 μm to100 μm. As an optical film, the insert 104 can have a thickness, forexample, ranging from 50 μm to 500 μm. As a rigid optic lens wafer, orlens blank, the insert 104 can be fabricated, for example, to have athickness of 0.1 mm to 7 mm.

Surrounding the diffractive region of the insert 104 can be a refractiveregion. The refractive region of the insert 104 can be of any opticalpower, including plano. By including a refractive and diffractive regionof differing optical powers, the insert 104 of the present invention canbe considered to be a refractive-diffractive multifocal insert.

The host lens material 102 can have different indices of refraction onthe front and back surfaces of the multifocal lens 100. That is, thefront layer of the host lens material 102 can comprise a material thatis different from a material comprising the back layer of the host lensmaterial 102. The front and/or back surfaces of the multifocal lens 100can comprise refractive optics, elements or regions. For example, a fardistance zone of the multifocal lens 100 located in an upper region ofthe multifocal lens 100 can provide plano optical power while one ormore near distance zones located in a lower region of the multifocallens 100 can provide positive optical power. The radii of curvature ofthe front and back surfaces of the multifocal lens 100 can bepredetermined so as to generate known amounts of refractive opticalpower. The front, back or internal surfaces of the multifocal lens 100can comprise progressive surfaces or regions. The progressive regionscan be added by grinding and polishing, by free-forming, or by moldingor casting.

The multifocal lens 100 can comprise one or more index matching layers106 (which can also be considered index mediating, mitigating orbridging layers as may be used in the discussion below). The indexmatching layers 106 can be used to reduce reflection losses between thehost lens material 102 and the insert 104. The index matching layer 10can have, for example, a reflective index that is substantially equal tothe arithmetic mean of the refractive indices of the host lens material102 and the insert 104. Additionally, the index matching layer 106 canbe used as primer layer to promote adhesion between the host lensmaterial 102 and the insert 104 and while reducing the visibility of adiffractive region positioned on the insert 104. Index matchinglayers/mediating layers 106 may or may not be used depending upon thedifference between the indices of refraction between the host lensmaterial 102 and the insert 104. Additional details on the design anduse of index matching layers is described in U.S. patent applicationSer. No. 12/238,932, filed on Sep. 26, 2008, which is herebyincorporated by reference.

the multifocal lens 100 can provide multiple vision zones that are widerand exhibit less distortion than traditional multifocal lenses includingprogressive addition lenses. Further, the multifocal lens 100 canprovide the multiple vision zones with a significantly reduced orinvisible break between adjacent vision zones as compared to traditionalbifocal or trifocal lenses. A diffractive region of the insert 104 canprovide one or more constant, progressive or variable optical powersthat can be combined with the one or more constant, progressive orvariable optical powers provided by the surfaces of the host lensmaterial 102. The one or more constant, progressive or variable opticalpowers contributed in part by the surfaces of the host lens material 102can be provided by the front and/or back surfaces or layers of the hostlens material 102.

The optical powers provided by a diffractive region of the insert 104can be combined with the optical powers of the host lens material 102 asdescribed in U.S. patent application Ser. No. 12/059,908, filed on Mar.31, 2008, U.S. patent application Ser. No. 11/964,030, filed on Dec. 25,2007, and U.S. patent application Ser. No. 12/238,932, filed on Sep. 26,2008 each of which is hereby incorporated by reference in theirentirety. In general, the diffractive region of the insert 104 can befabricated to provide any desired optical power including, but notlimited to, any optical power within a range of +0.12 D to +3.00 D.Further, the diffractive region of the insert 104 can be positioned tobe in optical communication with the optical powers provided by the hostlens material 102 to provide any desired near distance add power withany corresponding desired intermediate distance corrective prescription.

The multifocal lens 100 can comprise a far distance viewing region thatcan comprise refractive optics (e.g., refractive regions of the hostlens material 102 in combination with refractive regions of the insert104). The multifocal lens 100 can comprise one or more viewing regions(e.g., far intermediate, intermediate and/or near viewing regions) thatcan comprise refractive optics, diffractive optics or a combinationthereof (e.g., refractive regions of the host lens material 102 incombination with diffractive regions of the insert 104.) The multifocallens 100 can therefore use the combination of refractive and diffractiveoptics positioned on one or more surfaces or layers to provide multiplevision zones of varying optical power. As such, the multifocal lens 100can be considered to be a refractive-diffractive multifocal lens.

By locating and distributing the desired refractive curves ordiffractive structures on multiple surfaces, layers or regions of themultifocal lens 100, each of which are in desired location for providingan appropriate and desired optical alignment with respect to oneanother, enables the multifocal lens 100 to provide multiple visionzones that are wider than traditional multifocal or progressive lensesas described n the related patent applications mentioned above.

The diffractive region of the insert 104 may or may not include anoptical power discontinuity. The diffractive region of the insert 104may not be visible to an observer of the multifocal lens 100.Specifically, because the diffractive structures of the diffractiveregion of the insert 104 can be fabricated to have minimal heights, thediffractive region of the insert 104 may be nearly invisible to anobserver—particularly when covered by another layer (i.e., the frontlayer of the host lens material 102). Further, any discontinuityintroduced by the diffractive region's optical power can introducelittle or no prismatic optical power jump. An image break introduced bysuch a discontinuity can be that of a prismatic image break, amagnification image break, a perceived clear/blur image break, or anycombination thereof. A change in optical power of approximately 0.08diopters (D) or larger may be considered as introducing a discontinuitythat causes such an image break. As described in the incorporated andrelated patent applications, any discontinuity can be located in aregion traversed by a wearer's line of vision between a near to fardistance region or can be located in the periphery of the diffractiveregion.

Overall, the multifocal lens 100 can comprise any number ofdiscontinuities (including no discontinuities). One or morediscontinuities can be introduced by a single diffractive region or bymultiple diffractive regions.

As previously described, the host lens material 102 and the insert 104can be fabricated from any material having different indices ofrefraction. The materials used to form the host lens material 102 can beany lens material described in U.S. application Ser. No. 12/059,908,filed on Mar. 31, 2008 or U.S. application Ser. No. 11/964,030, filed onDec. 25, 2007, including those listed below in Table 1.

TABLE I INDEX OF ABBE MATERIAL REFRACTION VALUE SUPPLIER CR39 1.498 55PPG Nouryset 200 1.498 55 Great Lakes Rav-7 1.50 58 Evergreen/GreatLakes Co. Trivex 1.53 1.53 44 PPG Trivex 1.60 1.60 42 PPG MR-8 1.597 41Mitsui MR-7 1.665 31 Mitsui MR-10 1.668 31 Mitsui MR-20 1.594 43 MitsuiBrite-5 1.548 38 Doosan Corp. (Korea) Brite-60 1.60 35 Doosan Corp.(Korea) Brite-Super 1.553 42 Doosan Corp. (Korea) TS216 1.59 32 TokuyamaPolycarbonate 1.598 31 GE UDEL P-1700 1.634 23.3 Solvay NT-06 RadelA-300 NT 1.653 22 Solvay Radel R-5000 NT 1.675 18.7 Solvay Byry 1.70 36Hoya Essilor High Index 1.74 33 Essilor

The difference in the refractive indices between the host lens material102 and the insert 104 can be any value such as, but not limited to,greater than 0.01. One skilled in the relevant art(s) will appreciatehow a diffractive region of the insert 104 can be designed to accountfor being placed between materials having a different refractive index(e.g., an index of refraction different from air) and provide a desiredoptical power. Further, the index of refractive of the host material 102can be larger than the index of refraction of the insert 104. This canresult in a thinner lens as any curves of the host lens material 102 canbe made to be flatter than if the index of refraction of the host lensmaterial 104 was smaller.

The insert 104 can be inserted or embedded into the host lens material102 (with or without one or more index mediating and/or matching layers106) by any known lens fabrication technique or process. For example,the insert 104 can be molded within the host lens material 102 when thehost lens material 102 is first fabricated and/or cast from liquid resinas a lens blank. The insert 104 can also be embedded between two lenswafers that form the from and back components of the host lens material102. The two lens wafers can then be adhesively bonded together so as toform the multifocal lens 100 as a lens blank. Additional detail onmethods of fabricating the multifocal lens 100 is provided in thepreviously mentioned related patent applications.

A diffractive region of the insert 104 can be embedded as an uncured orsemi-cured resin. The diffractive region can also be formed or insertedinto the multifocal lens 100 by injection molding, stamping, embossingor thermal forming. The diffractive region can also be fabricated bydiamond turning a mold or mold master (for use in subsequent moldreplications) that is then used to cast a desired diffractive optic.Thus insert 104 can be, for example, a material such as polysulfone,polyimide, polyetherimide or polycarbonate.

The insert 104 can alternatively comprise a layer of photo-sensitivematerial with uniform thickness (i.e., not initially comprising surfacerelief diffractive structures). The refractive index of thephoto-sensitive material can permanently and irreversibly change topredetermined value when exposed to optical radiation. Thephoto-sensitive material may be exposed to radiation in a patternpredetermined to form a desired diffractive optical power region. Forexample, a diffractive phase profile may be “written ” on thephoto-sensitive material by means of exposure through an optical mask ora scanning laser source. The optical radiation can be, for example,within the ultra-violet or visible wavelength bands, although otherwavelengths can be used.

FIG. 2 illustrates a front view 202 and a corresponding cross-sectionalview 204 of a multifocal lens of the present invention. The multifocallens depicted in FIG. 2 can be a lens blank. The multifocal lens has arefractive region 208 and a diffractive region 206. The refractiveregion 208 can provide desired optical power in an upper region andlower region of the multifocal lens. The refractive region 208 can be ofmy desired optical power. As an example, the entire refractive region208 can be of plano optical power. The provided optical power can varywithin the refractive region 208 as will be understood by one skilled inthe pertinent art(s).

The diffractive region 206 is shown to be cropped. In particular, thediffractive region 206 is shaped as a portion of a circle but is not solimited. That is, the diffractive region 206 can comprise any shape aspreviously mentioned. For example, the diffractive region can be asemi-circle. Additionally, the diameter of the diffractive region 206can be any value including, but not limited to, 40 mm. The diffractiveregion 206 can provide a constant optical power. As an example, thediffractive region 206 can provide +0.75 Diopters (D) of optical power.A discontinuity may result due to a step-up or step-down in opticalpower between the refractive region 208 and the diffractive region 206.

As shown in the side view 204, the multifocal lens comprises the hostless material 102 and the insert 104. As an example, the insert 104 canbe approximately 100 μm thick and can have an index of refraction of1.60. The insert 104 can comprise the diffractive region 206 and arefraction region 210. The refractive region 210 can provide any opticalpower including plano optical power. As such, the insert 104 can beconsidered to be a thin refractive-diffractive multifocal optic.

The host lens malarial 102 that surrounds the insert 104 can be arefractive single vision leas. The host lens material can be finished onthe front convex curvature and can be unfinished on the back side of thesemi-finished lens blank. The host lens material can have any index ofrefraction, including, but not limited to, a refractive index within therange of 1.30 to 2.00.

The optical power of an upper region of the multifocal lens (e.g., theoptical power of the overall refractive region 208) can be provided bythe refractive region 210 of the insert 104 and the refractive regionsof the host lens material 102. The optical power of a lower region ofthe multifocal lens can be provided by the diffractive region 206 of theinsert 104. Once the back unfinished surface is finished by surfacing orfree forming, the multifocal lens depicted FIG. 2 can be a bifocal lenshaving an add power of +0.75 D. In general, the total add power of themultifocal lens depicted in FIG. 2 can be any add power as contributedby the diffractive structure.

FIG. 3 illustrates a front view 302 and a corresponding cross-sectionalview 304 of multifocal lens of the present invention. The multifocallens depicted in FIG. 3 can be a lens blank. The diffractive region 206can be a progressive diffractive region. Specifically, a top 306 of thediffractive region 206 can begin or start with a minimum optical powerthat can increase to a maximum optical power at a maximum optical powerregion 308. The diffractive region 206 can be formed by cropping.

As an example only, the minimum optical power can be plano optical powerand the maximum optical power can be +1.75 D. Alternatively, the minimumoptical power can be +0.25 D optical power and the maximum

optical power can be +1.00 D. A discontinuity may or may not result dueto a step-up or step-down in optical power between the refractive region208 and the diffractive region 206. For example, if the diffractiveregion 206 begins with an optical power that is substantially the sameas the optical power provided by the adjacent portion of the refractiveregion 208, then no discontinuity may result. Alternatively, if thediffractive region 206 begins with an optical power that is differentthan the optical power provided by the adjacent portion of therefractive region 208, then a discontinuity may result.

As shown in the side view 304, the multifocal lens comprises the hostlens material 102 and the insert 104. As an example, the insert 104 canrange from approximately 0.1 mm to 1 mm thick and can have an index ofrefraction of 1.60.

The host lens material 102 that surrounds the insert 104 can be arefractive single vision lens. The host lens material can be finished onthe front convex curvature and can be unfinished on the back side of thesemi-finished lens back. The host lens material can have an index ofrefraction, for example, of 1.49. The optical power of a lower region ofthe multifocal lens (e.g., one or more near distance vision zones) canbe provided by the progressive diffractive region 206 of the insert 104.

Once the back unfinished surface is finished by surfacing or freeforming, the multifocal lens depicted in FIG. 3 can provide multiplevision zones with multiple or varying optical powers provided by theprogressive diffractive structure 206. When the multifocal lens isfinished, and the progressive structure begins with a power that issubstantially the same as a power provided in a distance region (e.g., atop 306 of the diffractive region 206 and the refractive region 210 areboth plano), then the multifocal lens can be considered a multifocalprogressive addition lens. Alternatively, when the multifocal lens isfinished, and the progressive structure begins with a power that variesfrom a power provided in a distance region (e.g., a top 306 of thediffractive region 206 and the refractive region 210 are not bothplano), then the multifocal lens may be considered to be different froma traditional progressive addition lens yet still provide a progressionof optical powers.

The multifocal lens depicted in FIG. 3 can have its front surface and orback surface free formed or digital surfaced to provide an additionalincremental add power region. Further, this additional incremental addpower can comprise a spherical add power or a progressive optical powerand can be in optical communication with the diffractive structure 206.

FIG. 4 illustrates a front view 402 and a corresponding cross-sectionalview 404 of a multifocal lens of the present invention. The multifocallens depicted in FIG. 4 can be a lens blank. The diffractive region 206can be a progressive diffractive region. Specifically, a top 306 of thediffractive region 206 can begin or start with a minimum optical powerthat can increase to a maximum optical power at a maximum optical powerregion 308. The diffractive region 206 can be formed by cropping.

As an example only, the minimum optical power can be +0.01 D (or, e.g.,+0.25 D) and the maximum optical power can by +1.00 D. A discontinuitymay result due to a step-up in optical power between the refractiveregion 208 and the diffractive region 206 (e.g., if the diffractivestructure 206 contributes to an optical power that is 0.08 D orgreater). For example, the refractive region 208 may be of plano opticalpower such that a step-up in optical power results between therefractive region 208 and the diffractive region 206.

The multifocal lens can further comprises a progressive optical powerregion 406. The progressive optical power region 406 can be refractiveprogressive optical power region. The progressive optical power region206 can be located on the front or back surface of the multifocal lens.For example, the progressive optical power region 206 can be added bymolding or by free-forming. The refractive progressive optical powerregion 206 can be positioned anywhere on a surface of the multifocallens so that any portion can overlap any portion of the diffractivestructure 206. The progressive optical power region 406, as an example,can begin with plano optical power and can increase to +1.00 D of theoptical power. As such, the progressive optical power region 406 canprovide a first incremental add power and the diffractive structure 20can provide a second incremental add power. Together, when aligned andin proper optical communication with one another, the first and secondincremental add powers can provide a total add power of +2.00 D.

As shown in the side view 304, the multifocal lens comprises the hostlens material 102 and the insert 104. As an example, the insert 104 canrange from approximately 0.1 mm to 1 mm thick and can have an index ofrefraction of 1.60.

The host lens material 102 that surrounds the insert 104 can be arefractive multifocal lens. The host lens material can be finished onthe front convex curvature and can be unfinished on the back side of thesemi-finished lens blank. The host lens material can have an index ofrefraction, for example, of 1.49. The optical power of a lower region ofthe multifocal lens can be provided by the progressive diffractiveregion 206 of the insert 104 in optical communication with theprogressive optical power region 406 of the host lens material.Additionally, one or more vision zones in the lower region of themultifocal lens can be solely more vision by the diffractive structure206.

Once the back unfinished surface is finished by surfacing or freeforming, the multifocal lens depicted in FIG. 4 can provided multiplevision zones with multiple or varying optical powers that can beprovided by the progressive diffractive structure 206 alone or incombination with the progressive optical power region 406.

In general, according to an aspect of the invention, a diffractiveregion of an insert of the present invention can provide a firstincremental add power and a refractive region of a surface of bulk lensmaterial can provide a second incremental add power. Together, the firstand second incremental add powers can provide a total desired add powerfor a multifocal lens of the present invention. This can be accomplishedby ensuring that the diffractive region of the insert (at least aportion thereof) is in optical communication with the refractive region(or regions) of the bulk lens material. Further, the diffractive regionof the insert and the refractive region (or regions) of the bulk lensmaterial can be oriented or aligned to form multiple vision zones havingvarious optical powers as will be appreciated by one skilled in thepertinent art(s).

According to an aspect of the present invention, the diffractive regionof an insert of the present invention can provide 20% to 100% of thetotal desired add power of an overall lens. In many designs, it may bedesired for the diffractive region to provide 30% or approximately 33%of a total desired add power of a lens. Given an add power contributionprovided by the diffractive region, an add power of the refractionregions (s) of the bulk lens material can be determined. Further, inmany designs, the add power of the diffractive region can vary from+0.125 D to +3.00 D in steps of 0.125 D.

FIG. 5 illustrates a front view 502 and a corresponding cross-sectionalview 504 of a multifocal lens of the present invention. The multifocallens depicted in FIG. 5 can be a lens blank. The diffractive region 206can provide a constant optical power. The diffractive region 206 beformed by cropping. As an example, the diffractive region 206 canprovide +0.75 D of optical power. A discontinuity may result due to astep-up in optical power between the refractive region 208 and thediffractive region 206. For example, the refractive region 208 may be ofany optical power, including plano optical power, such that a step-up inoptical power results between the refractive region 208 and thediffractive region 206.

The multifocal lens can further comprise a progressive optical powerregion 406. The progressive optical power region 406 can be positionedanywhere on the multifocal lens and be positioned to be in opticalcommunication with the diffractive region 206. The progressive opticalpower region 406 can be a refractive progressive optical power region.The progressive optical power region 206 can be located on the front orback surface of the multifocal lens. As an example, the progressiveoptical power region 406 can begin with plano optical power and canincrease to +1.25 D of optical power. As such, the progressive opticalpower region 406 can provide a first incremental add power and thediffractive structure 206 can provide a second incremental add power.Together, the first and second incremental add powers can provided atotal add power of +2.00 D.

As shown in the side view 504, the multifocal lens comprises the hostlens material 102 and the insert 104. As an example, the insert 104 canrange

from approximately 0.1 mm to 1 mm thick and can have an index ofrefraction of 1.60.

The host lens material 102 that surrounds the index of 104 can be arefractive multifocal lens. The host lens material can be finished onthe front convex curvature and unfinished on the back side of thesemi-finished lens blank. The host lens material can have an index ofrefraction, for example, of 1.49. The optical power of a lower region ofthe multifocal lens can be provided by the progressive diffractiveregion 206 of the insert 104 in optical communication with theprogressive optical power region 406 of the host lens material.Additionally, one or more vision zones or regions can be located at orpreferably below a fitting point of the lens and can be solely providedby the diffractive structure 206. The fitting point of the lends can bea point on the lens that will align with the center of a wearer's pupil.

Once the back unfinished surface is finished by surfacing or freeforming, the multifocal lens depicted in FIG. 5 can provide multiplevision zones with multiple or varying optical powers provided by theprogressive diffractive structure 206 alone or in combination with theprogressive optical power region 406. The progressive optical powerregion 406 can begin above or below the diffractive region 206. Based onthe positioning of the progressive optical power region 406 and theoptical powers of the progressive optical power region 406 and thediffractive region 208 of the lens and a near vision region of the lens.

In general, a refractive-diffractive multifocal insert of the presentinvention can be combined with one or more other layers, surfaces oroptics as described in more detail in any of the previously mentionedrelated patent applications that have been incorporated by reference.

FIG. 7 illustrates a close-up view of possible alignment and positioningof the diffractive region 206 and the progressive optical power region406 in accordance with an aspect of the present invention. Specifically,FIG. 7 depicts a possible overlap between the upper portions of thediffractive region 206 and the progressive optical power region 406. Thediffractive structures of the diffractive region 206 are not shown inFIG. 7 for clarity only (instead, only a boundary of the diffractiveregion 206 is depicted).

As shown in FIG. 7, a top 702 of the progressive optical power region406 is aligned with the top of the diffractive region 206. A firstdistance 704 can correspond to a first change in the optical powerprovided by the progressive optical power region 406. Specifically, thefirst change can be from a beginning optical power value (e.g., zero D)to a first optical power value. A second distance 706 can correspond toa second change in the optical power provided by the progressive opticalpower region 406. Specifically, the second change can be from the firstoptical power value to a second optical power value. A third distance708 can correspond to a third changes in the optical power provided bythe progressive optical power region 406. Specifically, the changes canbe from a second optical power value to a third optical power.Accordingly, as shown in FIG. 7, the progressive optical power region406 can change from a starting optical power at the top 702 of theprogressive optical power region 406 to a third optical power value bythe end of a third distance 708.

The length of the first, second and third distances 704, 706 and 708, aswell as the corresponding first. second and third optical power valuescan be adjusted and modified to accommodate any ramp-up in optical powerwithin the progressive optical power region 406. For a sharp ramp up inoptical power, the distances 704, 706 and 708 can be designed to beshort and/or the power changes within each zone can be high. For slowramp up in optical power, the distances 704, 706, and 708 can bedesigned to be extended and/or the power changes within each zone can below. In general, the distances 704, 706 and 708 and corresponding powerchanges values can be designed to be any value.

As an example, each of the distances 704, 706 and 708 can be 1 mm inlength and the changes In optical power can be +0.03 D in the firstdistance 704, +0.03 D in the second distance 706, and +0.04 D in thethird distance 708. Under this scenario, the first optical power valueis +0.03 D, the second optical power value is +0.06 D, and the thirdoptical power value is +0.1 D.

As previously mentioned, the shape of the diffractive region 206 is notlimited to the shape depicted in FIG. 7. That is, the diffractive region206 can be any shape resulting from cropping including a portion of acircle. Any shaped diffractive region 206 can have a top that is alignedwith a top or start 702 of the progressive optical power region 406 asshown in FIG. 7.

A multifocal lens comprising an embedded or buriedrefractive-diffractive multifocal insert optic of the present inventioncan be fabricated according to any of the methods described in therelated and incorporated patent applications. As an example, therefractive diffractive multifocal insert optic of the present inventioncan comprise a preform. One or more external refractive layers can beadded to the preform by casting and curing an optical grade resin on topof the preform.

An example of this process is shown in FIG. 6. FIG. 6 shows a preform602. The perform preform 602 can comprise a refractive-diffractivemultifocal optic of the present invention. The preform 602 comprises arefractive region and a diffractive region 604. The diffractive region604 can be cropped. A resin layer 606 can be cast on top of the preform602 to form a multifocal lens 608 of the present invention. The resinlayer 606 can form a front surface of the multifocal lens. The resinlayer 606 can be later finished to include a progressive region. Theresin layer 606 can be cast and cured on preform 602. The resin layer606 or layer 602 can be photochromatic, polarized, tinted, include aselective high energy wavelength filter, or can form a portion of anelectro-active element. If layer 602 is photochromatic then layer 606can be selected of a material so as to block as little ultraviolet (UV)light as possible.

In the description above, it will be appreciate by one skilled in thepertinent art(s) that the diffractive structures employed above can bereplaced with refractive surface relief Fresnel optical power regions.Surface relief Fresnel optical power regions can comprise a series ofoptical zones that represent the shape of a conventional refractivesurface relief optical power region but modulated over a pre-determinedthiclmess. Such smface relief Fresnel optical power regions can besuperimposed on a substrate having a lmnown refractive index. As is thecase for refractive optics, Snell's law applies and can be used fordesigning the surface relief Fresnel optical power regions. For a givendesign of a surface relief Fresnel optical power region, the angle atwhich the light rays will be bent will be determined by the refractiveindex values of the materials forming the surface relief Fresnel opticalpower regions and the incident angle of said light rays.

Conclusion

While various embodiment of the present invention have been describedabove, it should be understood that they have been presented by way ofexample and not limitation. As such, all optical powers, add powers,incremental add powers, optical power ranges, refractive indices,refractive index ranges, thicknesses, thickness ranges, distances fromthe fitting point of the lens, and diameter measurements that have beenprovided are examples only and are not intended to be limiting. It willbe apparent to one skilled in the pertinent art that various changes inform and detail can be made therein without departing from the spiritand scope of the invention. Therefore, the present invention should onlybe defined in accordance with the following claims and theirequivalents.

1-13. (canceled)
 14. An ophthalmic lens having a far distance zone,comprising: a diffractive optical power region for providing a firstincremental add power; a discontinuity located between the far distancezone and said diffractive optical power region; and a progressiveoptical power region for providing a second incremental add power,wherein at least a portion of said diffractive optical power region andsaid progressive optical power region are in optical communication suchthat said first incremental add power and said second incremental addpower together provide a near distance add power for a user.
 15. Theophthalmic lens of claim 1, further comprising: a distance of saidprogressive optical power region corresponding to intermediate distancevision correction over which the optical power is constant.
 16. Theophthalmic lens of claim 2, wherein said distance of said progressiveoptical power region has a length of approximately 1 millimeter toapproximately 6 millimeters or greater.
 17. The ophthalmic lens of claim14, further comprising: a blending of optical efficiency across at leasta portion of said discontinuity.
 18. The ophthalmic lens of claim 17,wherein at least a portion of said blending of optical efficiency occursover a distance of approximately 2 millimeters or less.
 19. Theophthalmic lens of claim 14, wherein a portion of said lens provides anoptical add power for intermediate distance vision correction and saidoptical add power is between 45% and 55% of the optical add powerrequired for providing a user's near distance vision correction.
 20. Theophthalmic lens of claim 14, wherein the lens has a fitting point, andwherein the top of said diffractive optical power region is betweenapproximately 2 millimeters and approximately 5 millimeters below saidfitting point and the top of said progressive optical power region isbetween approximately 4 millimeters and approximately 8 millimetersbelow the top of said diffractive optical power region.
 21. Theophthalmic lens of claim 14, wherein said discontinuity is caused by astep in optical power.
 22. The ophthalmic lens of claim 14, wherein saiddiffractive optical power region is located on a surface of the lens orembedded within the lens.
 23. The ophthalmic lens of claim 14, whereinsaid progressive optical power region is located on a surface of thelens or embedded within the lens.
 24. The ophthalmic lens of claim 14,wherein said progressive optical power region comprises a progressiveoptical power surface generated by one of free-forming, molding, orcasting.
 25. The ophthalmic lens of claim 14, wherein said diffractiveoptical power region is generated by one of free-forming a surface ofthe lens, molding a surface of the lens, or casting a surface of thelens.
 26. The ophthalmic lens of claim 14, wherein a portion of saidlens provides an optical add power for far-intermediate distance visioncorrection and said optical add power is between 20% and 44% of theoptical add power required for providing a user's near distance visioncorrection.
 27. The ophthalmic lens of claim 14, farther comprising anear distance vision correction zone and a far-intermediate distancevision correction zone, wherein said progressive optical power regionprovides the optical add power for the far-intermediate distance visioncorrection zone in an area below the near distance vision correctionzone.
 28. A lens, comprising: a first layer having a first index ofrefraction, wherein the first layer comprises a far distance zone and afirst optical element; and a second layer having a second index ofrefraction different from the first index of refraction, wherein thesecond layer comprises a far distance zone and a second optical element,wherein an optical discontinuity occurs at a boundary of the firstoptical element and the far distance zone of the first layer due to astep-up in optical power between the first optical element and the fardistance zone of the first layer, wherein the first optical element islocated 4 millimeters below a fitting point of the lens, wherein thesecond optical element comprises a progressive optical power region, theprogressive optical power region contributing a second portion of atotal near distance add power of the lens, and wherein the first andsecond optical elements are in optical communication such that a firstportion of the total near distance add power of the lens and the secondportion of the total near distance add power of the lens are combined toprovide the total near distance add power of the lens.
 29. The lens ofclaim 28, wherein the first and second optical elements are aligned toform far-intermediate and intermediate vision zones.
 30. The lens ofclaim 29, wherein the far-intermediate vision zone has an add powerbetween approximately 20% and approximately 44% of the total neardistance add power of the lens and the intermediate vision zone has anadd power between approximately 45% and approximately 55% of the totalnear distance add power of the lens.
 31. A lens comprising: a firstlayer having a first index of refraction and having a first externalsurface and a second internal surface, a second layer having a secondindex of refraction different from the first index of refraction andhaving a first internal surface and second external surface, wherein thesecond internal surface of the first layer and the first internalsurface of the second layer are in physical contact to form a singleinterface, and wherein said interface comprises two optical zones, andwherein the second external surface of the second layer provides aprogression in optical power, and wherein an optical zone of saidinterface and the progression in optical power are in opticalcommunication for providing a combined optical power for correcting thenear distance vision of a user.
 32. The lens of claim 31, wherein one ofthe optical zones is diffractive and comprises surface reliefdiffractive structures.
 33. The lens of claim 31, wherein there is adiscontinuity in optical power between the two optical zones.